New mum Kate Winslet to sue parental organisation

They've used her photo in a Christmas campaign she calls "seriously defamatory"

Kate Winslet is threatening to sue a parents' rights group after the organisation used her image in a derogatory new campaign.

The ad in question, released by Britain-based Fathers4Justice, features a black-and-white photo of the 38-year-old Oscar winner above a slogan that reads: "Kate, every child deserves a father this Christmas."

It takes a dig at comments Winslet - who just welcomed a son with her third husband, Ned Rocknroll - made in a recent interview, in which she said her two children from previous relationships had a stable home life because they live with her.

"My kids don't go back and forth; none of this 50/50 time with the mums and dads - my children live with me; that is it," she said, referring to daughter Mia, to her first husband Jim Threapleton, and son Joe, to second ex-husband Sam Mendes.

Winslet's legal team have apparently issued Fathers4Justice with a legal letter stating the advert is "misleading and seriously defamatory" and asking that it be immediately removed from the public sphere.

Skyfall director Mendes has also entered the fray, telling the group: "It is inappropriate for this organization to involve my family and I when they know nothing of our personal circumstances. Whilst I fully support fathers rights I can happily state this has never been a concern for me or my son."

However, Fathers4Justice doesn't appear to be backing down, arguing it's simply highlighting Winslet's quote, rather than her personal family situation.

"We are running this advert as part of a campaign to highlight the sensitive issue of four million children waking up on Christmas Day without their father," a spokesperson said.

"It is clear from what Kate says that she does not support 'shared parenting.'"